1975 4 hp Evinrude bogging down

[heron2000]

This engine runs good but when running in high it slows down some - but when I take the cover off it really runs good. Like it can't draw enough air when the cover is on or maybe it's drawing exhaust and that's what is slowing it down. I tried drill 3 1/2 inch holes under the cover handle - it helped some.

any ideas - I'm thinking about changing the exhaust cover seal under the starter recoil.

[boats.net]

Look for signs of a exhaust leak on engine.